This invention relates to a blind rivet of the class so constructed that when the blind rivet is inserted through a fitting hole or fitting holes perforated in advance in one or more plate-shaped parts and the shank of the blind rivet which protrudes from one outer surface of the part is slid up the interior of the rivet body, the portion of the rivet body which protrudes from the opposite outer surface of the part is bent outwardly in the radial direction to the extent of securing the blind rivet fast of the part or uniting the two or more parts to one another, with ample allowance made for the size of the fitting holes perforated in the parts.
Various blind rivets of this class have been developed to date. In the light of the basic function these blind rivets are to fulfil in securing themselves in position relative to given parts or uniting such given parts to one another, however, those made of plastic materials prove to be advantageous over those made of other materials. Generally, the blind rivet of this class have a common basic construction which comprises a shank and a cylindrical rivet body formed round the shank by the two-stage plastic molding technique. Such a blind rivet is inserted through fitting holes perforated such as in panels until the flange or head of the rivet body thereof collides into the surface adjacent the edge of the fitting holes of the panels. Then, the shank alone is pulled up the interior of the rivet body with the aid of a tool. The pull of the shank causes the portion of the rivet body protruding from the other side of the panels to be bent outwardly and pressed against the panels, enabling the panels to be squeezed between the head and the bent portion of the rivet body.
Although these conventional blind rivets produce a force with which a plurality of panels will be pressed against each other, the stability with which these panels are secured to each other is insufficient unless the size of the fitting holes perforated in the panels and that of the shanks of the blind rivets inserted therethrough are substantially complimentary. If this tolerance is not controlled, the panels may possibly slip sidewise over each other and the blind rivets may possibly fail to give ample water-tightness to the fitting holes.
An object of the present invention is to provide a blind rivet of a plastic material which makes ample allowance for variations in the thickness of panels and the size of the fitting holes perforated in such panels; produces a strong force for holding the panels fast in position; provides high water-tightness to the fitting holes and manifests its effect to full advantage.